The present invention relates to a method of modifying the light-reflecting properties of the surface of a glass article, and more particularly to such a method which includes contacting the article with etching acid and subsequently rinsing it.
Various methods of modifying the light-reflecting properties of a glass surface are of course extremely well known. In perhaps the simplest method, the articles of glass are simply dipped into a bath of etching acid, withdrawn and rinsed. It is found that if rinsing is not performed immediately after withdrawal from the bath, the effect of the etching acid will in general be non-uniform due to the presence of excess droplets of acid still clinging to the surface. But it has also been found that the mere act of dipping, by itself, tends to render the treatment non-uniform, presumably because flow currents along the surface of the article as it is immersed and withdrawn, and convection currents within the bath, render the potency of the acid non-uniform from place to place on the glass surface.
It has also been proposed to spray-coat an article with etching acid. This however can lead to pitting.